MILLIMETRIC WAVELENGTHS RADIOWAVE PROPAGATION FOR LINE-OF-SIGHT INDOOR MICROCELLULAR MOBILE COMMUNICATIONS

With the increasing spectrum occupancy below 1 GHz, which is allocated to cellular personal and mobile radio, this paper exploits the use of millimeter waves where large signal bandwidths are available for indo or microcellular communications. The results of propagation experiment s conducted at 60.4 GHz (the oxygen absorption band) and 38.25 GHz to determine multipath characteristics in a number of indoor microcell ch annels employing omnidirectional antennas are presented, Cumulative di stribution functions for received signal envelope, as well as correspo nding power spectra are given, In addition, a comparison between the f ading statistics measured at 60.4 GHz and 38.25 GHz under similar cond itions is made, The change in multipath characteristics due to the pre sence of different building materials is also illustrated, A ray model is developed to represent indoor microcell propagation by considering a direct ray plus rays which have undergone single and double reflect ions from the walls, Specular floor-reflected and ceiling-reflected ra ys are included when the antennas radiation pattern does not preclude them, Using this simple model, the signal variations and the amplitude of reflected rays with respect to the line of sight (LOS) ray as func tions of mobile receiver position are predicted and used to assist in interpreting experimental results, Theoretical results are found to be in good agreement with measured ones, with the model also being used to predict structure-induced root mean square (rms) delay spread along receiver routes in an indoor microcell environment, This parameter is a measure of multipath conditions in a mobile radio channel and is in versely proportional to the maximum usable data signalling rate of a c hannel.